A car safety seat can save your child’s life, but only if it’s used properly. Consider the following common mistakes and how to avoid them.

Mistake: Not following the instructions

Test it: When correctly installed, a car seat shouldn’t wobble more than 1 inch in any direction. Push it from every angle to check its stability.

Fix it: If the car seat wobbles, read the seat’s manual. Many police or fire stations do free car seat inspections so check with your town.

Mistake: Poorly adjusted harness straps

Test it: Buckle in your child and check the fit. The straps should fit comfortably with no slack. The harness or chest clip should line up with your child’s armpits, not his or her belly or neck.

Fix it: Car seats often have multiple slots for the straps. You may need to rethread the straps through other slots as your child grows.

Mistake: Not knowing about a recall

Test it: Check for recalls on your car seat by contacting the manufacturer or by searching the National Highway Traffic Safety Administration’s recalls online at safercar.gov.

Fix it: Car seat manufacturers are required to notify the public about recalls. Register your car seat with the manufacturer either by mail or online to get recall information mailed or e-mailed to you.

Mistake: Not using a booster seat

Test it: After outgrowing their car seats, kids should use a booster seat until a seat belt fits properly without one. In a correct fit, the lap belt lays across the thighs and the shoulder belt fits straight across the chest.

Fix it: Booster seats are usually needed until a child is 8 to 12 years old or 4 feet 9 inches tall. Buy a booster seat that raises your child enough to have the seat belt fit properly.